Managing Critical Transition Zones

ABSTRACT Ecosystems that function as critical transition zones (CTZs) among terrestrial, freshwater, and marine habitats are closely connected to the ecosystems adjacent to them and are characterized by a rapid flux of materials and organisms. CTZs play various roles, including mediating water flows, accumulating sediments and organic matter, processing nutrients, and providing opportunities for recreation. They are particularly difficult to manage because they tend to be small, albeit important, components of large watersheds, and managers may not have control over the entire landscape. Moreover, they are often the focus of intensive human activity. Consequently, CTZs are critically important zones, and their preservation and protection are likely to require unique collaboration among scientists, managers, and stakeholders. Scientists can learn a great deal from the study of these ecosystems, taking advantage of small size and the importance of fluxes, but a good understanding of adaptive management strategies is needed to establish a dialogue with managers and stakeholders on technical and management issues. An understanding of risk analysis is also important to help set meaningful goals and establish logical strategies that include all of the interested parties. Successful restoration of a CTZ is the best test of the quality of knowledge about its structure and function. Much has already been learned about coastal CTZs through restoration projects, and the large number of such projects involving riparian CTZs in particular suggests that there is considerable opportunity for fruitful collaborations between scientists and managers

Simplified micturitional cystourethrography in female urinary incontinence

A new technique of mictional cystourethrography has been developed. The examination is performed with the patient sitting on a radiolucent chair with the feet high on a footstool, in order to avoid the superimposition of the femoral heads in the lateral projection. Fifty patients were examined, 26 of whom were continent and 24 incontinent. The technique allowed the evaluation of the site of the bladder neck, of vesico-urethral angles, and of the urethra. The investigation made it possible to obtain accurate information on the position of the vesical floor relative to the inferior margins of the obturator foramina. It was thus possible to correlate the position of the bladder floor with the clinical symptomatology: in our experience the position of the bladder floor was higher in incontinent that in continent patients. A low position of the bladder baseplate was usually associated with incontinence. Other parameters turned out to be less specific. This paper emphasizes the simplicity and the reproducibility of our technique, which allows a reduction of X-ray exposure dose

Renal echography in diabetes mellitus

The US findings in the kidneys of diabetic patients were studied. Diabetic subjects without clinical or laboratory signs of nephropathy were investigated by means of US in order to detect early anatomical lesions predictive of renal injury. The kidneys of cadaver diabetics were also studied to correlate US and histologic patterns. US alterations were observed in half of the cases: they were diffuse in 9% of cases and focal in 39%--hyperechoic spots and hyperechoic juxta-medulla. Focal spots are more common in juvenile-onset diabetics and they are correlated with the age of diabetes. At histology the above US patterns were correlated with the vascular wall alterations typical of diabetic nephropathy. Diffuse alterations are not specific. The authors conclude by suggesting US as a prognostic test for diabetic nephropathy

Primary fibromatosis of the breast: a case report.

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Echography: problems and errors in the diagnosis of renal masses

US plays an extremely important role in the diagnosis of renal masses. However, a number of diagnostic difficulties still exists in both identification of the mass and definition of its nature. The most frequent causes of diagnostic errors are discussed. Errors may be due to the radiologist, to technical limitations, and to the lesion itself. The radiologist is responsible for inexperience and negligence (incorrect application of the technique, limited clinical information, poor knowledge of US findings). Technical limitations are due to poor spatial and contrast resolution, to extremely fat patients, and to artifacts. As far as lesions are concerned, cystic and solid masses must be distinguished, since the problems are different. As for cystic lesions, problems are relative to their visualization and to the definition of their nature in cases of atypical or complex cysts, due to the complexity of some US findings. The latter involve both cystic wall and content and are related to calcifications, septa, vegetations, blood, purulent debris. In case of solid masses, problems concern the identification of small renal tumors, the differentiation among the various anatomical variants, the differential diagnosis of benign from malignant tumors, and the evaluation of tumor extent. The authors conclude that, whereas operator-dependent errors can be avoided, those inherent to technical parameters and to the lesion itself represent the diagnostic limitation of U